The present invention relates to an aircraft airfoil control system and more particularly, but not by way of limitation, to a system to adjust the camber of the airfoil in flight for optimum flight performance.
Heretofore, it was well known that any given airfoil design was a compromise between lift and drag. An airfoild was chosen for a particular aircraft according to the intended flight performance and use of the aircraft.
Various devices have been developed to adjust the airfoil's camber to alter the lift/drag ratio for special purposes. One such device is an aircraft's flaps normally used on landing.
With higher emphasis being placed on fuel efficiency, other devices have been developed to alter the camber of the airfoil while the aircraft is in flight to improve the aircraft's performance. One such device is described in U.S. Pat. No. 2,523,427, wherein the camber is adjusted by predetermined increments in response to the aircraft's airspeed measured at the pitot tube. The device described in this patent reacts only in changes in airspeed; however, during certain airspeed changing maneuvers a camber change would be detrimental rather than beneficial. Also, the device changes the camber to a hardwired chosen camber angle. There is no disclosure or suggestion in U.S. Pat. No. 2,523,427 of a device to dynamically adjust the camber in response to changes in the longitudinal velocity of the aircraft.
Other devices have been developed that optimize flight performance by either remotely effecting turn changes (U.S. Pat. Nos. 2,892,601) or by sensing and suppressing flutter in both leading and trailing edge wing surfaces 3,734,432). There is no disclosure or suggestion in either U.S. Pat. Nos. 2,892,601 or 3,734,432 of a device to dynamically adjust the camber in response to changes in the longitudinal velocity of the aircraft.